IRON AND COl'I'KR IN OVSTEU; 
29 
Carazzi who is mistaken, as we have found exactly the condition that Ryder describes 
in American oysters {see PI. VI., Fiy;. 7). 
In connection with this we may state that we have had tlie advantage of 
discussing very fully the iron and copper reactions, and Carazzi's statements and 
criticisms, with Professor A. B. Macallum, of Toronto, recently in our laboratory. 
Macallum, who is the author of the h;vmatoxylin method of demonstrating iron in 
tissue-cells, agrees with us entirely, and wishes to repudiate Carazzi's remarks in regard 
to the iron reaction 
Finding that we considered it necessar\- to take notice of Carazzi's papers, Dr. 
Macallum has asked us to insert the following note, which he had already written out 
for publication, as a statement of the method in which Carazzi has misinterpreted and 
misapplied his (IVIacallum's) and Zaleski's reactions : — ■ 
" In his reference to the literature Carazzi has, in some cases, been particularly 
inexact. He attributes to Macallum a method of liberating the organic iron of 
cellular elements (treatment with Bunge's fluid), in order to demonstrate it in the 
usual way, which that observer not only did not use, but also expressly describes 
as unsuitable for the purpose. Carazzi obtained negative results only with this 
method, the only one which he used, and yet he ventures on the basis of results 
so obtained to deny the correctness of Macallum's observations. In regard to 
Zaleski, Carazzi is almost equally inaccurate. Zaleski states specially that if the 
isolated liver-cells are extracted with physiological salt solution, and the residue 
subjected to artificial digestion after thorough peptonization, nucleins remain in 
which the iron can be shown ' nicht aber mehr durch die unmittelbare Anwendung 
der Eisenreagentien,' but after complete incineration only. One nuclein compound, 
not obtained in this way, did indeed give an immediate reaction for iron ; but 
Carazzi practically states that all the iron-holding nucleins isolated by Zaleski 
reacted immediately for iron, and then claims that this accounts for all the iron 
found in the nucleus by Macallum. An inexact knowledge of the literature on a 
subject is bad, but a criticism based on it is worse — it is mischievous." 
